Originally Posted by jhwisner
It means its derived from the magic described in the Dying Earth stories by Jack Vance - hence "Vancian." The short stories, originally published as early as 1950, described a world in which wizards had to commit spells to memory and where the spells left their memory whenever cast - as well as a host of other things which would be very familiar to anyone playing old school dnd. Some of the names names, purpose-built nature, and finite number of memorization "slots" were derived from these novels.

Yeah I figured that out on my own. The adjective "vancian" is a new made up word, though.